Added GPU process "echo" IPC message.

content/common/gpu/gpu_messages.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Multiply-included message file, hence no include guard here, but see below
 // for a much smaller-than-usual include guard section.
 
 #include <vector>
 #include <string>
 
@@ skipping 289 matching lines @@
 
 // Destroy a surface by routing id.
 IPC_MESSAGE_CONTROL1(GpuChannelMsg_DestroySurface,
                      int /* route_id */)
 
 // Create a TransportTexture corresponding to |host_id|.
 IPC_MESSAGE_CONTROL2(GpuChannelMsg_CreateTransportTexture,
                      int32, /* context_route_id */
                      int32 /* host_id */)
 
+// Request that the GPU process reply with the given message.
+IPC_MESSAGE_CONTROL1(GpuChannelMsg_Echo,
+                     IPC::Message /* reply */)
+
 //------------------------------------------------------------------------------
 // GPU Command Buffer Messages
 // These are messages between a renderer process to the GPU process relating to
 // a single OpenGL context.
 // Initialize a command buffer with the given number of command entries.
 // Returns the shared memory handle for the command buffer mapped to the
 // calling process.
 IPC_SYNC_MESSAGE_ROUTED2_1(GpuCommandBufferMsg_Initialize,
                            base::SharedMemoryHandle /* ring_buffer */,
                            int32 /* size */,
@@ skipping 30 matching lines @@
 // again to process any commands issued subsequent to unscheduling. The GPU
 // process actually sends it (deferred) to itself.
 IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_Rescheduled)
 
 // Return the current state of the command buffer following a request via
 // an AsyncGetState or AsyncFlush message. (This message is sent from the
 // GPU process to the renderer process.)
 IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_UpdateState,
                     gpu::CommandBuffer::State /* state */)
 
-// Indicates that a SwapBuffers call has been issued.
-IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_SwapBuffers)
-
 // Create a shared memory transfer buffer. Returns an id that can be used to
 // identify the transfer buffer from a comment.
 IPC_SYNC_MESSAGE_ROUTED2_1(GpuCommandBufferMsg_CreateTransferBuffer,
                            int32 /* size */,
                            int32 /* id_request (-1 means any) */,
                            int32 /* id */)
 
 // Register an existing shared memory transfer buffer. Returns an id that can be
 // used to identify the transfer buffer from a command buffer.
 IPC_SYNC_MESSAGE_ROUTED3_1(GpuCommandBufferMsg_RegisterTransferBuffer,
@@ skipping 38 matching lines @@
 // browser. This message is currently used only on 10.6 and later.
 IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_SetWindowSize,
                     gfx::Size /* size */)
 #endif
 
 // Tells the proxy that there was an error and the command buffer had to be
 // destroyed for some reason.
 IPC_MESSAGE_ROUTED1(GpuCommandBufferMsg_Destroyed,
                     gpu::error::ContextLostReason /* reason */)
 
+// Response to a GpuChannelMsg_Echo message.
+IPC_MESSAGE_ROUTED0(GpuCommandBufferMsg_EchoAck)
+
 // --------------------------------------------------------------------------
 // TransportTexture messages
 //
 // These are messages sent from renderer process to the GPU proess.
 
 // Destroy corresponding TransportTexture in the GPU process.
 IPC_MESSAGE_ROUTED0(GpuTransportTextureMsg_Destroy)
 
 // Notify that the textures have been created. IDs are in client context.
 IPC_MESSAGE_ROUTED1(GpuTransportTextureMsg_TexturesCreated,
@@ skipping 82 matching lines @@
 
 // Confirm decoder has been reset.
 IPC_MESSAGE_ROUTED0(AcceleratedVideoDecoderHostMsg_ResetDone)
 
 // Decoder has faced end of stream marker in the stream.
 IPC_MESSAGE_ROUTED0(AcceleratedVideoDecoderHostMsg_EndOfStream)
 
 // Video decoder has encountered an error.
 IPC_MESSAGE_ROUTED1(AcceleratedVideoDecoderHostMsg_ErrorNotification,
                     uint32) /* Error ID */